The present invention relates to a tube bending machine of the type including a bending templete provided with a groove receiving a portion of the tube being bent, and a clamping device holding the tube wrapped about the template.
Upon bending tubes in which some curved portions are adjacent to the next curved portion, without the provision of straight intermediate portions therebetween, and also upon bending tubes which have at their head ends the shape different from that of the remaining length of the tube, for example tubes having an enlargement or a welded flange before the curved portion, the exchange of the clamping surfaces on the bending template and also on the claiming jaw is necessary. Many various designs have been proposed to obtain an interchange of clamping surfaces.
German Pat. No. 26 26 202 of the applicant has disclosed the clamping jaw pivotable about a horizontal axis whereby the clamping faces of different embodiments have been arranged on the periphery of the clamping jaw and have been brought into action as desired.
European patent application No. 012,0336 filed by the applicant has disclosed supporting surfaces on the bending template and the clamping jaw, respectively, and particularly a recess for interchangeably-receiving of clamping elements having clamping faces, and wherein each clamping element is mounted on a guide and provided with a hydraulic drive which imparts to the clamping element in the recess the vertical movement so that out of a plurality of different clamping faces arranged one under the other only one or the other clamping face appears in the plane of the groove of the bending template.